From 8d7ecd085631e1dc0e5e37c6de6c936f56d42e38 Mon Sep 17 00:00:00 2001
From: Lukas Stockner <lukas.stockner@freenet.de>
Date: Sun, 4 Feb 2024 00:07:53 +0100
Subject: [PATCH] Cycles: Use high value for Transparent BSDF PDF

The transparent BSDF is singular, so MIS shouldn't be applied.

Fixes #117657.
---
 intern/cycles/kernel/closure/bsdf_transparent.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/intern/cycles/kernel/closure/bsdf_transparent.h b/intern/cycles/kernel/closure/bsdf_transparent.h
index 287f30cfc44..b0c6093e0da 100644
--- a/intern/cycles/kernel/closure/bsdf_transparent.h
+++ b/intern/cycles/kernel/closure/bsdf_transparent.h
@@ -76,8 +76,9 @@ ccl_device int bsdf_transparent_sample(ccl_private const ShaderClosure *sc,
 {
   // only one direction is possible
   *wo = -wi;
-  *pdf = 1;
-  *eval = one_spectrum();
+  /* Some high number for MIS. */
+  *pdf = 1e6f;
+  *eval = one_spectrum() * 1e6f;
   return LABEL_TRANSMIT | LABEL_TRANSPARENT;
 }